Aim #1 is to examine the factors associated with people's decisions on where to be tested, particularly whether they choose to be tested at home, doctors' offices, or public clinics. After 10 years of debate, the FDA approved the first home collection HIV test in 1996. Previous surveys found that a large percentage of the U.S. population could be likely to use home collection tests, including those who had not been tested and who were at high risk. We now have the unique opportunity to examine who is actually using home collection tests and how users' characteristics compare to individuals tested elsewhere, using data from nationally representative surveys and other sources. We will also collect new data and analyze existing data on individuals' preferences for different testing sites and methods, examine trends over time in how many people are tested and where they are tested, and compare te actual rates of use of home collection tests to how many people stated that they would use these tests before they were available. Aim # 2 is to examine the cost-effectiveness of a range of testing sites and methods, including home collection tests. The approval of home collection HIV tests opens the door to new testing technologies that promise to dramatically change the nature of HIV testing, including rapid tests, oral fluids tests, urine tests, and self- testing ("true" home tests with instant results). New HIV tests may change the cost effectiveness of testing programs and policies by changing the willingness of individuals to be tested, the number of persons found to be HIV- positive, and the cost of testing. We will therefore conduct a cost-effectiveness analysis of testing alternatives which incorporates the unique data obtained from the first aim of the proposed study. We will examine the policy implications of our findings, including how new testing methods can facilitate the early identification of HIV -infected persons and their entry into care; the implications for individuals, providers, and policymakers of the shifting of costs and benefits as a result of new tests; and the economic, social, and ethical issues that will arise because of new testing technologies.